rocksdb/table/iter_heap.h
2016-02-09 15:12:00 -08:00

43 lines
1.2 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
#pragma once
#include "rocksdb/comparator.h"
#include "table/iterator_wrapper.h"
namespace rocksdb {
// When used with std::priority_queue, this comparison functor puts the
// iterator with the max/largest key on top.
class MaxIteratorComparator {
public:
MaxIteratorComparator(const Comparator* comparator) :
comparator_(comparator) {}
bool operator()(IteratorWrapper* a, IteratorWrapper* b) const {
return comparator_->Compare(a->key(), b->key()) < 0;
}
private:
const Comparator* comparator_;
};
// When used with std::priority_queue, this comparison functor puts the
// iterator with the min/smallest key on top.
class MinIteratorComparator {
public:
MinIteratorComparator(const Comparator* comparator) :
comparator_(comparator) {}
bool operator()(IteratorWrapper* a, IteratorWrapper* b) const {
return comparator_->Compare(a->key(), b->key()) > 0;
}
private:
const Comparator* comparator_;
};
} // namespace rocksdb